Production of various kinds of rigid polyurethane foam is known in the art. Such production is typically carried out by subjecting a mixture of organic polyisocyanate and polyol having more than two hydroxy radicals per molecule to polyurethane foam-forming reaction conditions. Usually the reaction is catalyzed, e.g. by including an amine or tin compound in the reaction mixture. Also typically included in the mixture are secondary blowing agents (e.g. Freon) to lower the density and surfactants (e.g. silicones) to improve the uniformity of the resulting foam. Such catalysts, surfactants and blowing agents are normally added in relatively small proportions, but they are expensive. Hence the quantities in which they must be used have a significant impact on manufacturing cost of the foam.
Accordingly, it would be very advantageous if significant properties of the foam could be improved without need for more of such expensive constituents of the polymerization mixture, or if foams of equivalent properties could be produced while using smaller quantities of such constituents. An object of this invention is a rigid polyurethane foam-forming composition which provides those advantages. Another object is to provide the rigid polyurethane foams produced therewith. Other objects of this invention will be apparent from the following in which, except where otherwise noted, percentages are by weight and temperatures are Celsius.